PLATE II. 



(The specimens are figured natural size except when otherwise stated.) 



FIGS. 1,2. Valvata helicoidea Dall, magnified four diameters. The umbilicus 

 is partly hidden by a calcareous deposit ; p. 123. 



3. Lymncea petersi Dall ; p. 66. 



4, 5. Lymncea anticostiana Dall ; p. 79. 



6. Lymncea ? perpolita Dall; p. 78. 



7. 9. Lymncea atkaensis Dall; p. 66. 



8. Lymncea ? perpolita Dall, magnified two diameters ; p. 78. 

 10, n. Planorbula christyi ~D&\.\, magnified two diameters; p. 99. 



